Gun Safety
by scrub456
Summary: Sherlock really has no clue when it comes to the proper handling of a firearm. Fortunately for him, John does, and he's determined to teach Sherlock everything he knows. Even if it kills them both.


"This is non-negotiable, Sherlock." For once John was the one pacing the sitting room, pinching the bridge of his nose with his left hand while his right hand hung to his side, a loose grip on Sherlock's Browning, the muzzle pointed at the floor.

With a groan that seemed to originate from the very deepest depths of the bleakest despair, Sherlock sunk more puddle-like into his chair. Clad in three day old pyjamas and his robe, hair unkempt and askew, he was the very portrait of misery. John counted two... no, three nicotine patches stuck to his flatmate's arm.

"Sooooo... boreddddd..."

"That is no excuse, and you know it. _This_ is a weapon, not a toy." John held the gun up, on the flat of his palm. "You cannot just fire a gun inside a residence simply because you're a lazy git. We've discussed this. At length." He glanced at the smiley face on the wall... And the new grouping of three bullet holes just to the right of the old ones. It _was_ a fairly tight grouping, nicely done for an amature... _No. Just, no._ "You could kill someone!"

Heaving a great sigh, Sherlock flapped his hand noncommittally. "Yes, mum."

John put the gun on the table and stood in front of Sherlock with his arms crossed over his chest. "You listen here, Sherlock. You aren't taking this nearly seriously enough. You know shite about guns and gun safety, and I aim to correct that. Until then, I'm keeping yours."

"Like hell you are," Sherlock sat upright, eyes fierce and flashing. "I've read..."

"I don't give a rat's arse what you've read. Ever been to a shooting range? Physically practiced technique? Maintenance? No? No, you have not. All you've done is destroy Mrs. Hudson's wallpaper, and come dangerously close to hitting the ancient electrical wiring." Squaring his shoulders and planting his feet more firmly, John's glare was unrelenting.

"Oh, if _you_ can do it, how difficult can it be?" Rolling his eyes, Sherlock flopped back in his chair. "Just because you got yourself shot doesn't make you an expert," he mumbled.

Dropping his arms to his side and clenching his hands into fists, the corner of John's mouth twitched. "You're right." His tone was cold and emotionless. Sherlock jerked his head up, brow furrowed, calculating gaze assessing John.

"Getting shot doesn't make me an expert, it just makes me the poor sod whose only option was to take a flat share with you."

"John..." Did Sherlock actually sound apologetic?

Holding his hand up, John shook his head. "What makes me an expert is years of having it drilled into me, day and night, over and over, by men who would have kicked my arse if I'd even dared to look like I was bored." John sat in his chair and leaned forward with his elbows on his knees. Sherlock watched his every move intently.

"Sherlock, you are the unerring expert in... God... Just about everything. But in this, this _one_ thing, I know a little bit of something that you might not. So please, can we do this my way? Just this once?" John sighed and looked down at his feet.

"Fiiiiine." Sherlock attempted disdain, but the slight quirk of a smile gave him away. "If it'll stop you blathering on."

"Fine?" John's eyes were wide in surprise.

Sherlock sighed. "John. Repetition."

"Right. Good. Okay, lesson number one, and our most non-negotiable rule: Never. Ever. Fire your gun inside the house. For any reason. Ever."

"But John..."

" _Non_ -negotiatable."

* * *

John could hear the argument from the street. Actually, he could hear a voice that he thought should probably sound familiar screaming curses and threats. When the almost-familiar-but-not-really voice would cease for a beat, John didn't need to be a consulting detective to know Sherlock was providing his lofty smart arse retort in that low threatening tone, which would just set the other voice to carrying on once more.

Sending a quick text to Lestrade, John opened the front door without a sound. He made his way stealthily up the stairs, taking care to skip step number thirteen entirely, and silently thanked Sherlock for demanding they practice for just such an occasion.

Releasing the breath he'd been holding, John relaxed marginally when he discovered the door to the sitting room was closed. He continued his silent ascent up to his room, retrieved the Sig from his side table, inserted the clip and checked the safety. He made his way back down to the landing and crept through the door to the kitchen.

Peering carefully around the corner, John took in the scene playing out in the sitting room. Sherlock was seated in his chair, his posture seemed relaxed, one leg crossed over the other, hands wrapped around the edges of the armrests, but John could read very real tension in his friend's carefully schooled face.

In front of Sherlock, back to John, was a woman screaming threats and brandishing a gun. Taller than average height, athletic build, broad-ish shoulders, long mousy brown hair pulled back in a braid. She was wearing a uniform. John had seen that uniform recently... He stepped out from his cover just enough to ensure he'd be seen by Sherlock - Sherlock would later deny the relief the flashed just briefly on his face - and so he could see the woman's reflection in the mirror above the fireplace.

Catherine Cusack. Damn it.

Cusack was the assistant of some high society, no-one-really-knows-why-she's-famous, flavor of the month diva, and co-conspirator with one James Ryder, an employee of the posh hotel where Cusack's boss was staying. Cusack knew her boss kept a small wealth of jewelry in the safe in her suite. Ryder, as fortune would have it, worked in hotel maintenance. And to make the plan even more appealing, Ryder's newest hire, a John Horne, already had a criminal record and was the perfect person to frame.

Ryder had hidden the jewelry in plain sight, in the hopes that no one would find it before he and Cusack could collect it and and make their getaway. But someone hadfound it, and had brought it to Sherlock. The consulting detective had relished the idea of a puzzle he could work backwards, because really, how often did one start a mystery of lost jewelry by first obtaining the lost treasure and then locating the rightful owner?

Realising he was caught out, Ryder had showed up at Baker Street and begged them not to have him arrested. Since the jewelry had been returned - John had secured it in a safe deposit box and Sherlock had passed the info on to the diva's head of security with a warning not to trust the scheming assistant - Sherlock sent Ryder away with the threat to leave London and never attempt crime again, as he was terrible at it and sure to be found out. Ryder had heeded the warning and disappeared.

And that left Catherine Cusack, the scorned co-conspirator. She'd been fired from her position as assistant to the socialite, and been left to assume Sherlock still had possession of the jewelry. So, here she was to collect.

Judging by the piercing pitch of her voice, and the way she kept adjusting her grip on the gun, John surmised that Cusack was absolutely as bad at crime as Ryder had been. But Ryder hadn't actually threatened anyone's life. Cusack would not be extended the same kindness.

Cusack raged on, and true to form, Sherlock cut down her threats with scathing deduction and revealing observations, serving only to wind her up even more. John rolled his eyes and released a silent sigh as Sherlock verbally decimated the woman once more. He waited for Cusack to start in on her threats and then quietly stepped around into the sitting room and stopped at the back of his chair, directly behind her, with his gun at the ready.

Sherlock watched John's approach with rapt attention. He was distracted enough that when Cusack asked him a question his answer was not as immediate as she thought it should be.

"Oh, out of smart arse comebacks, are we?" Cusack spat out, briefly ducking low to speak directly in Sherlock's face. "Ugh, I'm tired of this. If you won't tell me where the jewelry is, maybe I should just kill you now. It can't be that hard to find in this place." She took another step forward and cocked her gun, aiming at Sherlock's head.

"I really wouldn't." It didn't take a genius to hear the warning in John's tone.

"Doctor Watson..." Cusack had probably wanted to say more, but could only manage a very nervous, slightly hysterical sounding laugh at the fact that she had been caught. Her shoulders drooped, and John recognized the exact moment she resigned herself to the fact that she was in very serious trouble.

Damn it. John swore to himself as Cusack raised her arms. Bloody buggering hell... She brought the gun down hard on the side of Sherlock's head. It didn't knock him out, but it stunned him enough that she had time to turn on John with her gun. He heard her safety click off as she turned, and he flicked his off as well. With shaking hands she leveled her weapon. John's shot was fired only a fraction of a second more quickly than hers.

John crashed to the floor behind his chair. Cusack dropped immediately at Sherlock's feet. And for being slightly concussed, Sherlock's response was surprisingly immediate.

"John!" With an enraged, and possibly horrified cry, Sherlock was on his feet. He wrenched the gun from Cusack's hands, and quickly noted the location of her wound. Shot to the abdomen, non-lethal, pity, yet fully incapacitating. Typical John.

Sherlock made his observations and was around the chair in a few quick steps. He dropped to his knees next to his friend. "John?"

"'M fine. Not hit." John swatted away Sherlock's hands as he sat up and tucked his gun away. He rolled his left shoulder and grinned. "Floor broke my fall."

Sitting back on his heels, Sherlock chuckled. "You'recertain you're all right?"

"Fine."

"I thought for sure..." Sherlock ducked his head and cleared his throat.

"She's terrible at crime. It was a pathetic attempt. When will these idiots learn?" John chuckled. "You'll not be rid of me that easily. Not because of the likes of her."

"Yes, well, there is another matter of some importance we must now discuss, John." Sherlock stood and extended his hand to help John up as well.

"Yeah?" Hearing sirens approach, about bloody time, John opened the door to the sitting room and then turned to Sherlock expectantly.

"Well, it appears, John, that you've committed quite the egregious sin." With a devious grin, Sherlock shoved John's chair to the side so it would be out of the way. "You've broken your own rules. Rule number one, in fact. Do not..."

"...Fire weapons in the house." Crossing his arms over his chest, John feigned giving it deep thought. "In my defence, so did she. And she also broke rules two and three just while I was standing here. She really had to be stopped. We can't have people breaking the rules just any time they please." John shrugged as he knelt beside Catherine and began assessing her wound.

Sherlock hummed his agreement. "Baker Street would descend to chaos."

"Well, most days we aren't far off. Tea towel." John grinned and held out his hand for the towel Sherlock tossed to him. He applied pressure to the wound. "Perhaps we should propose an amendment to the rule. A peril clause, if you will."

"Peril clause? I thought it was non-negotiable." Laughing outright, Sherlock stepped aside as Lestrade rushed in with Donovan and a group of medics close behind.

"Maybe a little negotiatable after all."

"Bloody hell. What now?" Lestrade took in the scene, and looked from John to Sherlock.

Standing to get out of the way so the medics could get to work, John glanced at Sherlock. "She broke the rules."

"She... Broke the rules? What does that mean?"

"Typically it means John works himself into a strop. There's usually shouting. And insults." Sherlock blinked innocently.

"Oi, you. Watch it." John chuckled and stepped to the kitchen to wash his hands. "I've broken a rule today too. Who knows what I'm capable of."

* * *

***Author's Note***

If you're familiar with the original Sherlock Holmes stories, I'm sure you recognized the case mentioned above. This was me taking modern day liberties with one of Doyle's most known tales, "The Adventure of the Blue Carbunkle." I always did wonder about Miss Cusack.

Also, after a bit of discussion with a fellow author/friend on AO3 - this story is actually part of a series we're co-writing over there, the series is "Baker Street Boot Camp" if you're interested - we mutually agreed that the fact John uses a Sig Sauer to shoot the cabbie while Sherlock has a Browning at the pool is most likely a production error. Then we also agreed that we're fic writers, and we can do what we want. So for this story, there are two guns at Baker Street. And isn't that just terrifying.


End file.
